In conventional textile machines of this type there is generally provided a main motor which may be directly coupled with, say, a driven feed roller and drives the other components, whose operation is to be correlated with that of the feed roller, via respective mechanical speed changers. Any modification of the speed ratio in such a system requires a change of gears and thus entails a considerable delay.
It has already been proposed to use digitally adjustable solid-state frequency inverters for the drive of certain elements of textile machinery; see an article entitled "TEXTILE APPLICATIONS OF ADJUSTABLE-FREQUENCY DRIVES WITH DIGITAL RATIO CONTROL" by Edward H. Dinger, IEEE Transactions on Industry Applications, Vol. IA-8, No. 1, January/February 1972, pages 47-55. As far as we are aware, however, there have been no suggestions heretofore regarding the utilization of this technique for the solution of problems encountered in correlating the operations of the diverse components of a ring spinning or twisting machine.